There are proposed various inventions relating to such a device. The device is worn on a body of a user to detect physical movements of the body by a sensor and the movement condition is determined based on the detected data so as to be used for health control and other objectives. For example:    (1) Japanese Patent Application Laid-Open 10-295651 discloses a technique wherein a mobile terminal having an acceleration sensor is worn on a waist of a user. Personal data stored beforehand and the quantity of movement which is automatically measured are transmitted to an external central computer by telephone line and analyzed for health check, and the result is transmitted to the movable terminal and displayed as required by the user.    (2) Japanese Patent Application Laid-Open 2000-41953 discloses a technique where a movement data collecting device has a physical movement sensor for detecting movements and is worn on a body of a user. The detected data undergoes a primary process and are transmitted to an external personal computer. A movement data output device provided in the computer carries out a secondary process based on personal information and the processed data is transmitted. The device renders it unnecessary to accumulate the personal information and the large size secondarily processed information therein so as to improve the operability and reduce the memory capacity thereof.    (3) In Japanese Patent Application Laid-Open 2000-41952, in order to reduce the memory capacity of a movement information detecting device, a built-in MPU calculates step count, walking pace, the type of movement, strength of the exercise, consumed calorie and other bodily information based on the output of a sensor and a movement detecting circuit, and stores, displays or externally transmits the calculated result every minute.
The devices in the above described conventional inventions (1), (2) and (3) are not small enough and are therefore often burdens to users.
An object of the present invention is to provide a small and a lightweight device which will be less burdensome to the user when worn.